Deprecate canPlayType for media elements in favor media capabilities

[marcoscaceres]

What is the issue with the HTML Standard?

It may not be possible to deprecate the canPlayType() API, but maybe we can encourage user agents to display a warning and also discourage further specify these capabilities for media elements and instead use w3c.github.io/media-capabilities/.

[annevk]

That looks like a lot more sophisticated API indeed, but for a number of cases prolly all you need is a tri-state? It at least seems much more involved to invoke that API if all you're after is some information about a MIME type.